Taking Images of Lecythidaceae

This article was contributed by Scott A. Mori and Nathan P. Smith

Herbarium specimens provide a great deal of information, but photographs taken in the field markedly increases their value, making it well worth the extra time expended. This is especially true for plants with fleshy flowers and woody fruits such as Lecythidaceae. In addition, bole form and bark characteristics of this family are more effectively communicated through images. Digital images are especially informative because they can be attached to specimen records in databases and, in turn, displayed on web pages.

Although images without voucher specimens can be useful, the images become much more valuable when they are documented with herbarium specimens. In the Brazil nut family, photographs of the two best-known species, the Brazil nut (Bertholletia excelsa Bonpl.) and the cannon ball tree (Couroupita guianensis Aubl.), have some value without specimen vouchers because they are relatively easy to identify based on images alone. Nevertheless, even easy-to-recognize species such as these should be vouchered by collections. In contrast, most other species of Lecythidaceae are more difficult to identify and, thus, herbarium vouchers are required to confirm the identity of the species represented by images. In addition, in some databases images of specific collections are attached to the specimen records so, without a collection, it may be difficult to make the images available online in collection-centered databases.

It is critical for monographers to photograph the characters used in the classification of their groups. For example, in the Lecythidaceae the flowers possess features that are lost when they are dried, especially over excessive heat, and the seeds have arils that are not easy to observe when the fruits are dry because dry fruits are difficult to open, and the arils are modified by the drying process. In addition, there are many bark features of Lecythidaceae that go unrecorded on herbarium specimens.

Although adequate pictures can be taken with a handheld point-and-shoot camera (especially for display on the Internet), the best images are obtained with an SLR digital camera. The smallest aperture available in most point-and-shoot cameras is f8, whereas an SLR camera has stops up to f32. The higher the f-stop, the greater the depth of field; and the greater the depth of field, the better the focus on the fine detail of the object photographed. Shooting pictures with a tripod reduces camera shake, allows images to be taken without a flash (under certain conditions), and permits shooting at slower shutter speeds. The colors of images captured without flash are more true to life, and this seems to be especially true of trunk and bark features. However, under the low light conditions of tropical forests, a flash is usually needed and, in those situations, we have taken satisfactory photographs using a ring flash for close-ups and the built-in flash for overall trunk and bark images (decreasing the intensity of the flash by placing a thin piece of white tissue over the flash will, however, improve the color rendition). A tripod improves even images captured under flash because it insures that the camera doesn't shift in between the time that the image is composed and the moment that the shutter is released. A plant holder for photography can be used to secure stems, leaves, flowers, and fruits while they are being photographed. A black velvet cloth the size of a herbarium sheet is useful as a background for certain kinds of photographs, especially those that mimic the herbarium sheet that the fresh specimens will become (see item 9 below). Whenever possible, small (five cm long paper labels with one millimeter divisions) should be included to give an indication of the size of the structures being photographed (see item 9 below). Enough space should be left on the rulers to write at least the name and number of the collection. For bark, the rulers can be held with push pins and for other structures, for example a picture of the branches on a black velvet cloth, the ruler can be held in place when it is windy by taping a coin to its back. The first and final images of a collection should include a paper ruler with the collector's name and number written on it—this brackets all images vouchered by the same collection thereby reducing the possibility of incorrectly naming the files when they are being processed. A single-edged razor is recommended for cutting longitudinal sections of flowers or cross sections of ovaries. A strong knife, chisel and hammer, or even a saw may be needed to open the woody fruits of some species of Lecythidaceae.

For those sending images for posting on the Lecythidaceae Pages, please send them at a resolution of 72 to 100 pixels/inch and a width of 700 pixels. A higher resolution can not be displayed on a computer screen and a wider width will take up more than can be seen in the image viewer. Because each image takes considerable work to handle, please send only the best images of each object rather than sending all of the images taken and do not send images that more-or-less show the same features. Finally, all images should be vouchered by herbarium collections and the data found on the specimen label should be sent with the images. It is extremely helpful if the images are labeled with the collector and collector number or put into a folder named with the same information.

We use the following protocol for taking digital images of Lecythidaceae

1. Habit. Pictures of the growth forms of Lecythidaceae are difficult to photograph in their natural habitats because most species are understory, canopy, or emergent trees difficult to distinguish from other trees unless they have been left in the open after deforestation. Some species, especially those that grow in more-or-less open areas on nutrient-poor soils, are small trees or even shrubs. The most striking habit difference in Lecythidaceae is that between pachycaul (sparsely branched trees with large leaves clustered at the ends of thick branches) and leptocaul (much-branched trees with small to medium-sized leaves scattered toward the ends of relatively slender branches) growth forms. According to the system of Hallé et al. (1978), there are at least six different architectural types in Lecythidaceae (Prance & Mori, 1979). Unfortunately, the plants usually have to be observed when they are young to photograph the different architectural types.
2. Bark. Images should give an idea of the general appearance of the bark. In the Lecythidaceae, there are sometimes striking differences in the barks of closely-related species. For example, the fissured bark (= bark fissured in our glossary) of Corythophora rimosa is very different from the scalloped bark (= bark scalloped) of C. alta. To best demonstrate the relationship between the thickness and color of the inner and outer barks photograph of an oblique cut of the bark, called a slash or blaze, is made. However, trees in reserves should not be cut or slashed unless permission is granted by the Reserve's management, and then the cuts should be painted with a fungicide and bacteriocide . The best bark pictures are taken under natural light with the camera held on a tripod, because the colors are more true than when a flash is used.
3. Trunk. In Lecythidaceae, the most important trunk difference is that some species are cylindrical (= trunk cylindric), are buttressed (= trunk buttressed), and a few a swollen (= trunk swollen) in various ways. One species possesses pneumatophores (= pneumatophore). The best trunk pictures are also taken under natural light with the camera held on a tripod.
4. Specimen image. Once the collected branch is on the ground, a piece of stem with attached leaves, and flowers and/or fruits, are placed on a colored cloth (we prefer blue) along with a ruler. Ideally the collector's name and number should be added to the image. At least one leaf should be turned to show the abaxial surface because some species are characterized by leaves having surfaces with different colors. Inflorescences and fallen empty fruits should be included if they are present. This photograph provides a color image similar to the herbarium specimen that will be prepared from the fresh specimen. If the collection is lost, a print or online display of this image can used as a substitute for it.
5. Stem. This image should show the bases of the petioles and the apex of the stem. If young stems differ from older stems, both should be photographed.
6. Petiole cross-section. To standardize position, the cross- section is made at the junction of the petiole and the blade. To demonstrate the petiole's orientation in relation to the leaf blade, the base of the blade should be visible.
7. Inflorescence. The inflorescence is usually included in the specimen image taken on colored cloth. Sometimes additional more detailed images are needed to show its branching pattern, the orientation of the rachis (straight or zig-zag), the shape and persistence of the bract and bracteoles, and the presence or absence of a pedicel.
8. Flowers. Apical, lateral, and basal views of flowers show the pedicel (when present), the orientation and imbrication of the calyx-lobes, and petal orientation. In Lecythidaceae, a medial longitudinal section of the flower shows the structure of the androecial hood (e.g., flat or coiled, and the presence or absence of appendages or a protective external flap), the nature of the style (well-defined or difficult to distinguish from the summit of the ovary), its orientation (erect or oblique), and the presence of absence of a stylar collar. Medial and cross sections of the ovary of flowers or very young fruits show the type of placentation of flowers in both cross and medial longitudinal section. Single-edged razor blades are useful for making the floral sections.
9. Fruits. Apical, lateral, and basal views of the fruits show the position of the calycine ring, the orientation of the infra- and supra-calycine zones, and the persistence of the pedicel. In addition, the operculum is photographed to show the presence or absence of an umbo (the style remnant) and columella (a projection from the operculum into the fruit).
10. Seeds. Photographs of fruit with mature seeds in situ are taken to demonstrate seed arrangement. The seeds are then removed and photographed in the following ways: lateral and basal views of the seeds to show seed coat surface, venation pattern, and whether the veins are impressed, plane, or salient. Special care needs to be taken to remove the seed so that its attachment to the fruit wall is shown so that the presence or absence of an aril is documented. Most often species of Lecythidaceae have funicles that are surrounded by arils, but in some species this is difficult to see unless the seeds are removed without destroying the funicle and or aril. In other species the aril completely surrounds the seeds (this is called a spreading aril in contrast to a basal or a lateral aril).

Literature Cited

Hallé, F., R. A. A. Oldeman & P. B. Tomlinson. 1978. Tropical Trees and Forests: An Architectural Analysis. Springer-Verlag, Berlin. 441 pp.

Prance, G. T. & S. A. Mori. 1979. Lecythidaceae-Part I. The actinomorphic-flowered New World Lecythidaceae (Asteranthos, Gustavia, Grias, Allantoma, & Cariniana). Flora Neotropica Monograph. 21: 1-270.